Telephone system



6 Sheets-Sheet l B. VANDER ELs TELEPHONE SYSTEM Filed sept. 9, 1942Sept. l2, 1944.

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Sept. 12, 1944. B.'vANDER ELS l TELEPHONE SYSTEM 6 Sheets-Sheet 2 Filedsept. 9.' m42 v. .E RE mn u. m NE. E0 .A wm.. fm m. e@ ou B. VANDER ELSTELEPHONE SYSTEM 6 Sheets-Sheet 3 x Ill Filed Sept. 9. 1942 /N VEA/TORSept. 12, 1944. B. VANDER ELS 2,358,267

. TELEPHONE SYSTEM Filed Sept. v9. 1942 6 Sheets-Sheet A.

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AroRA/E B. VANDER ELS TELEPHONE SYSTEM Sept. 12, 1944.

Filed Sept.' 9, 1942 /NVEN 729A BVB. MINDER ELS v Arron/wv e Smets-Sheete Sept. 12, 1944. B. VANDER ELS TELEPHONE SYSTEM Filed Sept. 9.' 1942/N'l/EA/rof? By l B. MINDER ELS WWW VM# ArmR/ry Patented Sept. ll2, 1944UNITED STATES erreur f orties assazsv TELEPHONE SYSTEM ApplicationSeptember 9, 1942, Serial No. 457,697

15 Claims.

This invention relates to automatic switching telephone systems and moreparticularly to the control of pulse-responsive devices for suchsystems.

It is the object of the invention to simplify the equipment forcontrolling revertive impulseresponsive devices.

Some telephone systems known in the art are controlled by the directimpulse method and others by the revertive impulse method. The directimpulse method is used for positioning step-by-step switches or otherpulse-responsive devices in which the regulating factor is the pulsetransmitter, such as a dial'or pulse repeater. The revertive impulsemethod is used in large telephone oices, such as the panel or crossbaroflice systems, in which a fundamental circuit is formed between acontrol device and apulsing device for positioning switches or registersin a sender. This pulsing device may be in the form of a switchcommutator or a register controlling relay which in present systems isregulated under the control of a series of counting relays which aremarked according to the number of direct pulses received by the controldevice having the counting relays therein. When the fundamental circuitis closed by a control circuit relay, the distantly related pulsingdevice operatescontinuously in synchronous relation with the countingrelays until the fundamental circuit is opened by a particular countingrelay. Ordinarily there are ten pairs of counting relays arranged tocount a maximum of ten pulses.

The registers of register senders, such as shown in the'crossbar systemof Patent 2,089,921 issued to W. W. Carpenter, August 10, 1937, are ofthe type which are positioned by the revertiveV impulse method, afundamental `circuit being shown between the pulsing relays of thesender and the counting relays of another circuit. The same controlcircuit arrangement has been used for operating and testing senders andit has been found to be a matter of economy to test ten or more senderssimultaneously. This requires a large number of sets of counting relaysand other`l associated equipment for controlling the number cf pulsestransmitted. Y

It is a feature of this invention to associate a simple dial with thecontrol part of the revertive impulse fundamental circuit to functionwith the pulsing equipment of a sender for the operation of the senderregister equipment. f

Another and related feature resides inthe use of one dial in place of alarge plurality of counting relays for simultaneously controlling theoperation'of a plurality of revertive impulse sendersY for testing theoperation of said senders.

These and other features will be discussed more fully in the followingdescription.

Toillustrate the invention and the economy in the use of the invention,reference may be had. to the accompanying drawings, in which:

Fig. 1 illustrates aplurality of senders diagrammaticallyV in the leftportion of the 'figure associated with a digit control circuit intheright and lower-portion of this figure;

Fig. 2 illustrates the remainder of this digit control circuit;

Figs. 3 and 4 diagrammatically illustrate modifications ofthefundamental circuit using a dial in the digit control portion ofthis-circuit;

Figs. 5, 6, and 7 illustrate digit control circuits using countingrelays for simultaneously operating a plurality of senders showndiagrammatically inthe left portion of Fig. 5;

Fig. 8 illustratesV a telephone system having an operatorspositionequipped with a dial for controlling a revertive impulse sender;v i

Fig., 9 illustrates the order of assembling the sheets of the drawings.l f

In order to make a comparison from the viewpoint of economy andimprovement between the digit control circuit of the invention and otherdigit. control .circuits for revertive impulse systems, a shortdescription is given in the following paragraphs of the arrangement newin general use. f

A sender of the character operated by revertive impulses is disclosedand described in Patent 2,089,921 issued to W. W. Carpenter, August 10,1937. `This sender is shown in Figs. 29, 30 and 37 and described indetail in pages 20,`2122 and 23 of the specification. The fundamentalcircuit extends from a control circuit which may be in another sender,over leads 5819 and 5828 shown in Fig. 58 of this patent. The incomingconductor 58|!! may be traced to conductors 5826 and 3126 thence througha contact on relay 3100, a contact on relay 318 I, winding of what isgenerally known as the Lv relay 3015 to battery. The incoming conductor5821] may be traced to conductors 5825 and 3125 and thence through acontact on relay 3188, a contact on relay''llll, through the Vwinding ofwhat is generally known as the stepping or pulsing relay 300B to ground.The L relay 3045 is the equivalent of relay lll vor 9| shown in Fig. 1,508 or 5I0 lshown in Fig. 5, 3d@ shown in Fig. 3 and 440 shown in Fig.4. The stepping or pulsing relay 3080 is the equivalent of relay U3 or93 shown in Fig. 1, 552 or 562 shown in Fig.5, 342 shown in Fig. 3 andM12 shown in Fig. 4.

The fundamental for a control circuit which may be connected withconductors 58|9 and 5820 of Patent 2,089,921 is shown in sender circuitPatent 2,106,360 to R. Raymond, January 25, 1938. The latter patentincludes counting relays |220 to |234 and a control circuit steppingrelay |202 in Fig. 12 which are connected in the fundamental circuitextending through equipment, as described., to conductors 328 and 329 ofFig. 3 of the Raymond`patent. Conductors 326 and 329 may be connected tothe above-mentioned conductors 58|9 and 5820 of the Carpenter patent forcontrolling the number of pulses transmitted by the sender pulsing relayfor registering digits. The fundamental circuit and the method ofoperating the counting relays in Patent 2,106,360 may be traced from thedescription given on page 5, column 2, lines 11 to 74 of this patent,and need not be again described herein.

Again referring to Patent 2,089,921, it may be seen that a testoperation of the sender can be made by inserting a test circuit plug inthe jack shown in the left upper portion of Fig. 37 of the drawings forthis patent. The tip spring of this jack is connected throimh a. contacton relay 310|, winding of theL relay 30I5 to battery. The ring spring ofthis jack is connected through a contact of relay 310|, winding of thestepping relay 3000 to ground. As herein stated, the operation of thesender, the transmission of revertive pulses and the pulse recording bythe crossbar registers shown in Fig. 29 are fully described on pages 20,21 and 22 of this patent and need not be again described herein. In thedrawings of this application, Figs. l, 3, 4 and 5, and the registerequipment diagrammaticallyshown may be the same as shown in theACarpenter patent.

. A testing circuit following the practice used at the present time foroperating senders of the character shown in Patent 2,089,921is disclosedin Figs. 5, 6 and '7 of` the illustrated embodiment for thisapplication. In order that `the senders of an olice may be rapidlytested, this circuit is -arranged tosimultaneously operate ten sendersand for this purpose ten circuits, Fig. 6, areused, only one beingshown. The control equipment fused for Fig. 6, therefore, amounts to 200counting relays, 400 jacks, 50 plugs and other equipment forprogressively operating this circuit. v

Two senders are diagrammatically shown in Fig. which represent the rstand last of ten senders of the character shown in the aforementionedpatent to Carpenter. The jacks 503 and 5| 3 represent the jacks of tensenders herein referred Each relay in Fig. 7 has ten contacts forsimulof the jacks 605 to 609 as required for marking the counting relaysto control the number of counting relays to be operated for the incomingbrush digit. A similar plug is inserted in one of jacks 6|6 to 624 tocontrol the number of pulses in the incoming group digit. In the samemanner similar plugs are inserted in jacks 6I0 to 6|4 for the nal brushdigit, in one of jacks 625 to 634 for the tens digit, and in one ofjacks 635 to 644 for the units digit.

' The procedure in simultaneously operating ten senders for testingpurposes is rst to connect patching cords, such as 504 to 5|4, from thedigit control circuit jacks 505 to- 5|5 with sender jacks 503 to 5|3. Itmay be assumed that the ten senders thus patched to the control circuitare not in use at this time. Plugs such as 60| to 604 are inserted injacks, such as 605 to 644, one plug taneously establishing ten circuitswhen operated.

The jacks in the upper portion of Fig. 6 are arranged to control thenumber of pulses for each of the digits which will be herein known asin- -coming brush, incoming group, nal brush, final trolcircuit forsuccessivelyY registering different digits. A plug, such as is insertedin any being used for incoming brush in one of jacks 605 to 600, anotherplug being inserted in one of jacks 6|0 to 6|4, a plug in one of jacks6|6 to 624, a plug in one of jacks 625 to 634 and a plug in one of jacks635 to 644. As shown onthe drawings, these jacks are grouped forproperly marking the starting point of operation of the counting relaysin order that the correct number of pulses be counted by the countingrelays for each digit, 'and as shown on the drawings, these plugsregulate the number of pulses for the incoming brush, incoming group,nal brush, rlnal tens and nal units digits which are successivelyregulated by the control testing circuit as switch 120 rotates. Forstarting the operation of this test control circuit the start key 12| isoperated. This establishes a circuit for moving switch 120 from itsnormal position and advancing it to its second terminal. The circuit foradvancing the switch from its normal position may be traced from groundthrough the start key 12|, terminal and brush of switch arc 120C,contact and windingv of the switch magnet 120 to battery. Upon reachingterminal 2 a circuit is established for the incoming brush vrelay '|00which extends from battery through its winding, terminal 2 and brush ofarc 120A to ground on the start key 12|. A circuitfor lamp 604 is alsoestablished to this saine ground to provide an indication of theprogressive operation of the control circuit. The lamps 105, 106, 101and 1|2 are lighted when the associated relays are operated to show thesuccessive registration ofY the various digits. The operation of relayestablishes circuits through its'contacts 0 to 9 for controlling tensets of counting relays, one set being shown in Fig. 6, and alsoconnects ground through its contact i0, No. 2

Vcontact and brush of switch arc C, contact and winding of the magnet120 to battery which causes the switch brushes to step from terminal 2to terminal 3. Relay 100 remains operated since a circuit is alsoestablished in position 3 for this relay. The fundamental circuitbetween ten senders and the control circuit is now made effective by theoperation of relay 1||. The circuit for this relay may be traced frombattery through its winding, contact 3 of switch arc 626B to groundthrough the brush of this switch arc. At this time the pulsing relays ofthe ten senders are automatically operated until such time as thefundamental circuit is opened by the end Vcounting relays in each of theten sets of counting relays.

Let it be assumed that plug 60| was inserted in jack 601 marking thecounting relays for incoming brush selection. The counting relay oircuitmay thus be traced through a particular path as the relays of thefundamentalcircuit are actuated. It isv believed sufficient to trace thefundamental circuit for operating the Zero sender since the fundamentalcircuits for the other` nine senders are the same and, therefore,. neednot be traced. It may be assumed that ten plugs, such as 60|, are allinserted in a jack of the same number in ten sets of like jacks foroperating .the

Vlead 66|, contact of the end counting relay 050A,

lead 080,1ing spring of -jack.505, ring of` patching cord 504, ringspring of jack 503, winding of the sender pulsing or stepping relay 502to ground. The sender L relay 500, the sender pulsing-relay 502 and`thecontrol circuit stepping relay 508 operate in the circuit traced.Theoperation of` .relay 508 establishes a circuit for the operation of acounting relay which maybe traced from battery, through counting relay651B, spring of the sender stepping relay 502 andthe control cirf cuitstepping relay 508, causing theirf'release. Countingrrrelay 651A isshunted while relay- 508 is operated, but upon the release of relay 508it is operated in series with counting relay 651By from battery, throughthe windingsl of relays 851Band 651A, contact of relay 651B to ground onthe contact of relay 1|0. The release of relay 502 releases relay 50|and the fundamental circuit is again established foroperating the senderpulsing relay 502 Vand the control circuit stepping relay 508 totransmit a second pulse and opera-te another counting relay 858B.`Counting' relay 658Boperates through the inner contact of relay 051Ayto ground on the contact of stepping relay 508 over the circuit aspreviously traced through jack 601. As relay 502 transmits'a secondpulse to the register equipment, it also operates relay 50| which againshunts the stepping 4relays 502 and 508 causing their release, Thisremoves the shunt around the winding of counting relay 058A i which nowoperates in series with relay 658B, as described for the operation ofrelay 051A.` Relay 50| again releases thus permitting a third operationof stepping relays 502 and 508 'for transmitting a third pulse to thesender register equipment and `for operating a third counting relay650B.v The operation of relay 502 again operates relay 059A^andoperatesinseries withrelay V550B at the Sametime relay 859A isoperated. Thereis, of course, one relay 610 foreach of the ten sets of counting relays.Thus, while the fundamentalis held open, a circuit is established-fromground on the contact of relay 610, through the thirdcontact and brushof switch arc/120C, contact and winding of the switchmagnet v120 tobattery for' advancing the switch brushes to terminal 4. Relays and1||are released and a circuitis established for rela'ys '|00 and 1|0 uponthe rotation of the switch brushes from terminal V3 to terminal 4. Therelease of cut-in relay1|| 'opens the ten fundamental circuits extendingthroughy the contacts 0:1500 so rthat the fundamental oircuits willremain open after the count- :ing relays have been released. Theoperation of relays 100 and 110 opens the holding circuits extendingthrough their contacts 0 to '9 for all counting relays whichwereoperated causing vthe release of the counting relays. Relays 109 and 1|0establish a` circuit through contact l0 of both relays for operating theslow-release relay 123, the latter relay establishes an'obvious circuitfor Amoving*the'switch brushes fromV position '4 to position 5. Inswitch position 5 a circuit is established for incoming groupVr'elay'10l and progress f lamp 105. This circuit extends from battery,y

through the Awinding of the relay and lamp, terminal 5 and brush ofswitch arc 120A to ground on the contact of start key 12|. The operationof the incoming group relay 10| establishes acircuit for moving theYswitch brushes to terminal 6 which maybe traced from ground on contactI0 of relay 10|, terminal 5 and' brush of arc 120C, contact and windingofthe switch magnet to battery. It will be vnoted that in switchposition 8 'the Acircuit for the incoming group relay 10i remainsestablished. e

In switch position 8 a circuit is established for cut-inrelay 1|| whichisthe same as previously traced.` The fundamental circuits are nowestab- V.lished vrforincoming group pulses from'the ten senders to thecontrol circuit through the ten contacts of relay 1| The counting relaycontrol for group selection extends Aover circuits through thencethrough ten jacks, such as jack BIS, and ten plugs, such as 802, windingof counting relays,

such as 553B tov battery which operates the ten counting relays to-startthe control of the sender pulsing which proceeds in the same Vmanner aspreviously described until the fundamental is opened by the end countingrelays suchy as 658A.

The operationof theten senderswfor setting the registers under thecontrol of the counting relays as the switch '|20 advances is the samefor final brush, final tensand nal units and it is believed that thisoperation willbe well understoodv Afrom theV descriptionV herein givenso that vthe description of Figs.l 5, 6 and '7Amay be terminated at thispoint. Other devices, not shown,

are used for observing the operation of the senders and for restoringswitch '|20 to normal when a test is completed.

Figs. l and 2 diagrammatically show two of the same character of sendersas shown in the aforesimultaneously controlled andtested by the digitcontrol and testing circuit shown in these figures of the drawings. Thiscontrol circuit provides full control of the senders over the usualfundamental circuit Without the use of a large plurality of countingrelays and a large plurality of jacks such as shown in the controlcircuit of Figs. 5, 6 and 7. In the arrangement of Figs. 1 and 2 theoperation of the plurality of senders for setting the sender registersis under the control of a single dial and a progressively operableswitch.

The ten senders of Fig. 1 are connected to the control circuit byinserting patching cords and plugs 06 to 96 in the sender jacks 05 to 95and control circuit jacks 01 to 91 in the same manner as described forconnecting the senders of Fig. 5 with the control circuit of Figs. 5, 6and 7. The start key 201 is then operated which provides an obviousoperating circuit for the start Vrelay 206. This start relay providesground circuits for various operations which will be apparent in thedescription. Relay 222 is operated from battery through its winding toground on contact 2 of start relay 206. 'Ihis .relay provides signalingpaths for lamps 09 to 99 to indicate that the testing circuit isassociated with ten idle senders. This circuit extends from batterythrough lamp 09, contact of relay 222, sleeve of jack 01, sleeve ofpatching cord 06, sleeve of jack 05 to ground on the contact of thesender relay 04. A similar circuit may be traced for lamp 99 throughcontact 9 of relay 222. Other similar circuits extend through thecontacts of this relay. Relay 22| is energized from battery through itswinding, contacts 5 and 4 ofdial 220, to ground on contact 6 of thestart relay 206. Relay 22| places a shunt ground through its contacts tothe ring conductor of all senders which causes the release of the senderpulsing or stepping relays 03 to 93. released and operated a number oftimes during the backward movement of the dial after the dial hasbeenmoved forward to a particular position by the engagement of a particularfinger notch. The stepping magnet 2|0 is energized from battery throughits winding, brush and contact I of switch arc 2|0A, contacts I and 2 ofthe dial to ground on contact 8 of the start relay 206.

The switch does not, however, step its brushes to terminal 2 until thiscircuit is opened by the forward movement of the dial, since the switchis what is known as a backstroke switch. Lamp 236 is connected to thefirst` terminal as a signal showing that the switch is in the correctposition to begin the control of the senders. The circuit for lamp 236is from battery, through the filament of the lamp, terminal I and brushof switch arc 2|0,F, contact I0 of start relay 206 to ground.

The senders may now be controlled for incoming brush selection by themanipulation of the dial 220. It should be here pointed out that onepulse is registered in the sender when a jack of the sender is connectedby the patching cord to the jack in the control circuit since at thattime battery through resistance l0 or through resistance |00 isconnected through the winding of the sender pulsing relays 03 and 93which operates these relays. The operation of the pulsing relaysoperates relay 02 and relay 92 which in this instance operate the Lrelays 0| and 9| cause a pulse to be transmitted to the registerequipment of the senders. Th dial must therefore be manipulatedaccordingly so that the dial notch 4 will be used if the sender pulsingrelay is to It will be apparent that relay 2| is .f

operate live times. Assuming that the dial notch 4 is used for incomingbrush selection, the circuits are established in the following orderwhen the dial is moved off-normal. The forward movement of the dialopens the dial spring contacts l and 2 which openithe circuit for switchmagnet 2|0 causing the brushes 'to be stepped forward to position 2. Theforward movement of the dial causes the engagement of dial contact 2with dial contact 3 which establishes a circuit for the fundamentalrelay 20| from battery through the winding of this relay, contacts 2 and3 of the dial to ground on contact 8 of start relay 206. The latter dialcontacts remain closed and relay 20| remains operated until the dialreturns to its normalposition. The operation of relay 20| connectsground through its contacts 0 to 9, lamps 08 to 98, tip springs of jacks01 to 91, patching cords 06 to 96, tip springs of jacks 05 to 95,windings of L relays 0| to 9| to battery. This circuit maintains the Lrelay 0I operated 'during the non-pulsing periods of relays 03 and 02and maintains the L relays of the other nine senders operated during thenon-pulsing periods of the other' to 93 which operate over circuits'tobattery through resistances I0 to^|00 during the progress from notch 4to its normal position which causes relay 22| to be released andoperated four times. The release of relay 22| removes the ground shuntsfrom the operating circuits for the pulsing relays 03 to 93. Theoperation of relays 03 Vto 93 causes the operation of relays 02 to 92whichtransmit pulses to their respectively associated registers andmaintain operating circuits for other respectively associated L relays0| to 9| during this pulsing period. The operating circuit for the Lrelays 0| to 9| from ground on their respectively associated relays 02to 92 shunts the current Vsupply for lamps 08 to 98 during the pulsingperiod and thus indicates to an observer the number of pulsestransmitted as the dial returns to its normal position. Each operationof relay 22| establishes a shunt for pulsing relays 03 to 93 whichcauses the release of these relays and the release of relays 02 to 92.The return of the dialto its normal position opens the circuit for therelay 20| which opens the ten fundamental circuits. The L relays 0| to9| now release so Vthat the sender register equipment may beautomatically adjusted for receiving the pulses of the next successivedigit.

During the time that relay 20| was operated.,

which is equivalent to the forward and backward movement of the dial forcontrolling a series of pulses comprising a digit, a circuit isestablished through contact I0 of relay 20|, terminal 2 and brush ofswitch arc 2|0A, switch magnet 2|0 to battery. The return of the dial toits normal position separates dial contacts 2 and 3 which restores relay20| and opens the circuit extending through the winding of the switchmagnet, thus causing the switch to advance its brushes from terminal 2to terminal 3.v

The second manipulation of the dial controls the sender pulsing relaysfor incoming group J Y -2,358,267f selection in themanner as'describedfor incoming brush selection and the switch advances'one terminal uponthe return of the dial-to its normal y position. The third manipulationof the -dial controls final brush selections, the fourth -manipg ulationof the dial controlsnal tens selections,-

and the fifth manipulation of the dial controls nal units selections.These are the same selec-Y tionsas described for-the control circuit ofFig's.

5, 6; and 7 in which the counting relays controlled thenumber of pulsesvtransmitted by )thevsender arecOunted' equivalent'to' the `finger notchused in moving thedial forward' tothe linger stop. `It

will 'be noted that'by the use of'this modification; y

the pulsing relay `303' does not Voperate until the return movement ofthe dial and, thereforaa' pulsing relays into the sender registersinstead of having the number of pulses controlled by the .simple dial220. The 1amps`23| to 235 indicatem zthe progress of the control circuitin a similarl manner to the signallamps suchas 604 asso `ciated with therelays of Fig. 7.

Fig.. 3 illustrates amodication of the funda# mental circuitshown. inFigs. 1 and 2. The send- .er equipment is disclosed inithefleft portionand :the control circuit in the right portion of this'.

gure. -For this diagrammatic showing. of the 1 of this gure.

cuit. A stepping relay of this'chara'cter is used in the digitcontrolcircuitshow'n in Figs'. 5,16 and 'l for operating the countingrelays'fthrough its contact.;A 'It may'beassumed that the same" typefundamental, the progress switch isnot provided.

The particular diiference: between the'control circuit of Fig. 3 and thecontrol circuit of Figs. 1 and 2 resides in the use of relay 334whichisv operated from a contact of relay 346. Relay .346

may be assumedto be the same as relay 20| of Fig.V 2. e Relay 5345 maybe assumed to be the same as relay 22| of Fig. 1. Arelay, such as relay222, isnot shown. It may ber assumed that the senders are connectedvwithlthe control circuit by attaching cordsV inthe same manner as shownin Fig. 1. Thus thev senderin the left portion of Fig. 3 is connected tothe control circuit in the right portion of this figure. 'Ihe startrelay 335,

which may be substantially the same as the start relay 206.'.of Fig. 2,isoperated by the start key' 301. The operation of the startrelayconnects ground through contacts4 and 5 of the dial 350,

winding of relay 345 to battery, operating the latter relay. This placesa shunt on the pulsing `relay 303 so that it will not be operated untilsuch timeas the contactof. relay 345 is open upon the return movement ofthe dial after it has beenmoved to the finger stop` and released. Whenthe dial is moved forward from its'normal position, a circuit is closedfor relay 346 which connects ground through lamp 332, winding of the L`relay 30| to battery, operating the L relay. 'I'he operation of the Lrelayv establishes circuit of patching-cords as shown in Fig. f1 fareused for.Y

associatingthe digit controlv circuit of Fi'gfl with the senders of Fig.4. The operation of the lock`r ing ystart key "446 e'nergizes relay445-which associates ground with the fundamental circuit 'b'el-v 2tween'the windings ofY control'relay 444 and the l When thedial'is'movedforward' from its normal position, the funda" f mental circuit is closedthroughcontacts2fand '3" of the dial, winding 'of'rel'ay 444,"co'ntacts'and 3f of relay'445 to ground. The sender 'L vrelay 440 and r'e'lay444are thus energized from battery' through the winding. of .relay 440,resistance v446,' contacts 2 and'3 off'dial 450, winding of relay '444to groundfthrough contacts 3 and of relay 445.`

sender pulsing relay 442.

. At thistime `relay 442 is shunted by/ground from l 444 remainsoperated and its contact remainsA i open and consequently thesenderpulsing relayrv lfor operating yrelay 355 to prepare the registerequipment for receiving pulses when the pulsing relays 303y and 302 areoperated. .The operation of relay 346 also establishes a circuit foroperating 334. YThe operation of relay 334 connects battery throughresistance 333 to the ring conductor of the fundamental, but since atthis time ground is connected to the ring conductor of the funda--rmental, through the contact of relay 345, the pulsing relay 303 will notoperate. After the dial has been moved forward to the finger stop` andreleased, contacts 4 and 5 are intermittently open as the dial returnsto its normal position. The opening of contacts 4 and 5 causes therelease of v relay 345 which removes the ground shunt from ringconductor of the fundamental. 'Ihus a circuit is established for thepulsing relayl 303 iromground through its Winding over the ringconductor, contact of relay 334, resistance 333 to battery. Relay 303establishes an obvious circuit for relay 302 which transmits a pulse tothe register equipmentandrassqciates ground with the tip conductor forestablishinga holding circuit for' the L relay 30| during lthe pulsingperiod.

.the contacts'of relay 445.1The operation of the L relay 440.establishesan operatingV circuit for relay 441 to prepare the registering equipmentfor receiving pulses later 44| are'operated.- f f When the dial is movedforward to the nger stop and released, 'fthe dial contacts 4 and '5. areopen causing the rst release of relay 445. Relay' 442 operates in'serieswith 'relay 444 toibatter'y,

also lremains operated. `The operation of'relay 442 energ'izesv relayV44| relay 440 t' battery, holding the 'L' relay operated during thepulsing period. .A Connecting this ground with the tip lead also shuntsrelay 444 1 and relay V442 causing'their release and the release ofrelay 44 VRelays 442 and 444 operatev and 'release very rapidly and,"therefore, an

through contacts and2 of relay 445a`ndY the contact of'relay 444 to'shunt'relays 444 and 442 and maintain anoperati'ng circuit `for vthe Lrelay 440. j-Upon the next "closure of contacts' 4 and 5,

and3 of relay 445' to battery,Y throughfthe'wind;

is not registered by theregister'v n when relays 442-"and" whichtransmits 'a pulseV f into the registerV equipment and associates groundwiththe tip' lead through the winding' of the LY t5 arrangement ispro"videdr ytov prevent these' relays" from operating f again' if relay'445has not lbeen operatedby the time relays 442 and 444 have beenreleased'after relay 544| has transmitted the first pulse. If the'dial'contacts 4 and l5 havenot again 'closed;-and again operate relay445 whemrelay' 444 is "re-l leased; a' circuit is established 'frornground ing of the L relay 440. The operation of relay 444 opens itscontact so that the pulsing relay 442 operates again in series withrelay 444 when dial contacts 4 and5 open and release relay 445.

The pulsing continues inthis manner for setting the registers, and thedigit control circuitA equipment is maintained in synchronism with thepulsing equipment of the sender until the dial has returned to itsnormal positionrwhere the funda- ,mental circuit extending to the Lrelay 440 isi opened by dial contacts 2 and 3 causing the release of theL relay so thatthe register equipment may be automatically adjusted forreceiving the next digit. Relay 445 remains operated Vuntil vthe dial isagain moved forward and released for intermittently opening the dialcontacts 4 and 5 to register the next digit and during this time shunts thepulsing relay442 from ground through itscontacts I and 3. The dial isthus moved forward and released as many times as required forcontrolling the fundamental pulsing equipment to register a certainnumber of digits in the sender. The start key may then-be 'released forreleasing relay 445 after'the last equip such switchboard positions witha dial arranged for the direct pulsingmethod the same as a subscribersstationdial or with a key pulsmay operate a line finder 80| andselecting switch 802 of the usualV type known in the art, for connectingthe subscriber A with the operators position and the calling subscriberis challenged Vby the operator in the operators position to as# certainthe destination of the call. Various characters of telephone equipmentare contemplated for connecting the calling party with the operatorsposition. When the destination of they call requires the use of a"revertive pulse sender for setting the outgoing switches 830 and 83|, anoutgoing circuitl is selected by a plug or a switch extending to a linkfor connecting a revertive pulse sender with Ithe outgoing circuit fromthe operators position. Key 8 8 is actuated for connecting the digitcontrol circuit with the fundamental circuit and start key BIS isactuated which establishes an obvious circuit for relay 813. Theoperation of relay 8I3 establishes an operating circuit for relay 814through contacts 4 and 5 of the dial 8|9. Relay 8|4 connects a shuntground with one leg of the fundamental extendingtoward the winding ofstepping relay 822 of the revertive pulse sender.

The switchboard operator manipulates the dial 8|9 when an idle senderhas been connected to the operatorsposition circuit for regulating thenumber of revertive pulses comprising the first digit. The movement ofthe dial 8I9 away from its normal position closes the dial contacts 2and 3 which establishes an obvious operating circuit 5 for thefundamental closing relay. SI5. The latter relay connects ground throughits upper contact, lamp 8|0, right contact of key 8l8, winding of the Lrelay 820 to battery which operates theV L relay 820 and lights lamp8I0. The L relay 820 no-w establishes an operating circuit for revlay823 which establishes a circuit between relay ing key set, neither ofwhich are arranged for Y u controlling a revertive pulse sender.Therefore, when revertive pulse senders are associated with an operatorsposition, it has been the practice to place another sendery between theoperators position and the revertive pulse sender.

The sender which is used between the operators position and therevertive pulse sender may' be of the' type disclosed in Patent2,106,360 to R. Raymond, January 25, 1938, to which reference hasalready been made, or other senders of this character shown in the artwhich are set from directV dial pulses or by pulsing key sets and whichare arranged Yto convert or translaterthe digits registeredrfrom directpulses for controlling `a revertive pulse sender of the character shownby W. W. Carpenter in the aforementioned Pat-r ent 2,089,921.

The useV of the revertive pulse digit control circuit of the inventionin the operators position circuit as shown, eliminates the requirementfor a group'or plurality of senders of the type shown by Raymond betweenthe operators position and the revertive pulse senders, the lattersenders being controlled directly by the operators digit control circuitwhich includes a dial adaptable for such control instead of the directpulsing dial. The revertive pulse Vsender diagrammatically rshown inFig. 8 may be of the type shown in the aforementioned patent toCarpenter and the revertive pulse digit control circuit may be arrangedas shown in either Figs. 1 and 2, or the modifications Fig. 3 or 4.

An incoming call Yfrom subscribers station A 82| and the senderregisters over which a pulse is transmitted upon each operation of thesender pulsing relays 822 and 82|. Relay 8|5 also establishes 'anobvious circuit through its lower contact for operating relay 8|2. Thelatter relay connects batteryv through`resistance 8H and the` relaycontact, windingof relay 822 to ground. This circuit is however noteffective Afor operating relay 822 until relay8l4 isreleased to re-`move the shunt ground from this conductor of the fundamental circuit. P

The Vdia1 contacts 4 and 5 are opened after the switchboard operator hasmoved the dial to the finger stop by engaging a particular finger gripand the dial has been released. so that it mayJ return'to its normalposition. A linger grip is engaged by the operator according to thenumber of pulses to be counted for the digit. The opening of dialcontacts 4 and 5 releases relay 8|4 which removes the ground shunt fromthe associated leg of the fundamental circuit. Relay 822 now operatesfrom ground through its winding, contact of relay 8|2, resistance 8H tobattery. Relay 8:22 operates relay 82| over an obvious circuit and thelatter relay transmits the assage'? ber of times the dial contacts 4 and5 are opened as the dial returns to its normal position.

When the dial has restored to normal, contacts 2 and 3 are openedcausing the release of relay 8l5 which opens the operating circuit forthe sender L relay 820. The release of relay 820 signals the sender thatthe last pulse of the digit has been transmitted and adjusts theregistering equipment for receiving the pulses of the succeeding digitwhich are registered upon the next operation of the dial. Successiveoperations of the dial set the registers of the sender in the mannerdescribed, for controlling switching connections after the last digit isrecorded as shown in the aforementioned patent to W. W. Carpenter, forconnecting the calling subscriber A to the called subscriber B.

It is not contemplated that the invention be limited to the specificuses illustrated since there are other telephone system arrangements inwhich this revertive pulse control circuit may be used to effectconsiderable economies.

What is claimed is:

1. In a telephone switching system, a switch controlling circuit, adigit controlling circuit, a

' revertive impulse fundamental circuit extending from said switchcontrolling circuit to said digit controlling circuit, the switchcontrolling circuit portion of` said fundamental circuit comprising arelay operable by said digit controlling circuit during non-pulseperiods for arranging said switch controlling circuit for receivingpulses, and a pulsing device for operating said switch controllingcircuit and for holding said y relay operated duringr the pulsetransmitting periods, and means including a dial for closing saidfundamental circuit when said dial is moved forward from its normalposition, for

regulating the number of pulses transmitted by sender to said controlcircuit, the sender portion of said fundamental circuit comprising arelay operable by said control circuit during the non-pulsing period forarranging said registers for receiving pulses, and a pulsing device foroperating said registers with means in said pulsing device for holdingsaid relay operated during the pulse transmitting period, and meansincluding a dial for closing said fundamental circuit when said dial ismoved forward from its normal position, for regulating the number ofpulses transmitted by said sender pulsing device to said registers onits backward motion and for opening said fundamental circuit uponarriving at its normal position.

3. In a telephone switching system, a plurality of switch controllingcircuits, a digit controlling circuit, a revertive impulse fundamentalcircuit extending from each of said plurality of switch controllingcircuits to said digit controlling circuit, the switch controllingcircuit portion of each fundamental circuit comprising a relay operableby said digit controlling circuit during Ynon-pulsing periods forarranging each switch cuits and for holding said relays operated duringthe' pulsetransmittingV periods, and meansl including a single dial forcausing 'the closure of said plurality of fundamental circuits when saiddial is moved forward from its normal position, for regulating on itsbackward motion the number ofpulses transmitted by the pulsing devicesin each of said switch controlling circuits and for causing the openingof said yplurality of fundamental circuits upon arriving in its normalposition.l I Y 4. In a telephone switching system, a switch controllingcircuit, a digit controlling circuit, a revertive impulse fundamentalcircuit extending from said switch controlling circuit to said digitcontrolling" circuit,v the switch controlling circuit portion of saidfundamental circuit comprising a relayoperable by said digit controllingcircuit during non-pulsing periods for arranging said switch controllingcircuit for receiving pulses, and a lpulsing device for operating said fswitch controlling circuits and for holding said relay operated duringthe pulse transmitting period, the digit controlling circuit portion ofsaid fundamental circuit 'comprising a dial having springs thereon whichare open when the dial is in its normal position and closed when theldial, is moved from its normal position, and other springs which areintermittently opened and closed during the backward movement of saiddial, means for closing said fundamental circuit and operating saidrelay by the closure of said first springs withv the `dial moved fromits normal position, and means for regulating the number of pulsestransmitted by said pulsing device by the movement of said other springsduring the backward movement of said dial to normal where saidfundamental circuit is again opened responsive to the opening of saidfirst springs..

5. In a telephone switching system, a switch 'controlling circuit,` adigit controlling circuit, a

revertive impulse fundamental circuit extending from said switchcontrolling circuit to said digit controlling circuit, the switchcontrollingcircuitVV portion of said fundamental circuit comprising arelay operable by said digit controlling circuit during non-pulsingperiods for arranging said switch.y controlling circuit for receivingpulses and a pulsing device for operating said switch controllingcircuit and for holding said relay op- `erated during said pulsetransmitting period, the digit controlling circuit portion of saidfundamental circuit comprising a dial and means to close saidfundamental circuit by movement of "said dial away from its normalposition which establishes an operating circuit for the relayv in saidswitch controlling circuit before the pulsing circuit in saidfundamental is established, and other means forestablishing a circuitfor the pulsing device and for regulating the number of lpulses in adigit during its backward movement to its normal position where saidfundamental `circuit is again open by said rst means.

6. In a telephone switching system, a switch vcontrolling mechanism,registers, a digit controlling mechanism, a revertive impulsefundamental circuit extending from said switch controlling mechanism tosaid ydigit controlling mechanism, pulsing devices in the switchcontrolling portion of said fundamental circuit for transmitting pulsesto said registers and for transmitting equivalent revertive pulses oversaid fundamental circuit for controlling said pulsing devices, a dial insaid digit Icontrolling mechanism,`a synchronizing device in saidcontrolmechanism under the control of said revertive pulses and said dial andmeans in said dial in combination with means in said synchronizingdevice for regulating the number of pulses in each digit. Y Y

7. In a telephone switching system, a plurality of switch controllingsenders having digit registers therein, a digit ycontrolling circuit,revertive impulse fundamental circuits i extending from said pluralityof switch controlling senders to said digit controlling circuit, pulsingdevices in the switch controlling portion of eachy of ysaid fundamentalcircuits for transmitting |pulses to said respective registers and fortransmitting equivalent revertive pulses over said respectivefundamental circuits for controlling said pulsing devices, a single dialin said digit controlling circuit, a synchronizing device in saidcontrol mechanism under the control of said revertive pulses and saiddial and means in said dial in combination with means in saidsynchronizing devi-ce for regulating the number of pulses for each digitfor setting the registers in said' plurality of switch controllingsenders.

8. In a telephone switching system, switches, incoming lines, outgoinglines, a telephone operators position, means for connecting an incomingline with said operators position, a revertive pulse sender havingregisters therein for controlling switching connections to connect anincoming line to an outgoing line, a revertive pulse digit controllingmechanism in said operators position, a revertive pulse fundamentalcircuit extending` from said digit controlling mechanism to said sender,means for connecting said digit Icontrolling mechanism to saidfundamental circuit, pulsing devices in the sender portion of saidfundamental circuit for transmitting pulses to said sender registers,and means including a dial in said digit controlling mechanism forclosing said fundamental circuit to establish circuits for said pulsingdevices and for regulating the number of revertive pulses in each digitto set the registers of said sender for establishing a connectionbetween said incoming digit controlling mechanism in said operatorsposition, a revertive pulse fundamental circuit extending from saiddigit controlling mechanism to said sender, a key for connecting saiddigit controlling mechanism to said fundamental circuit, pulsing devicesin the sender portion of said fundamental circuit for transmittingpulses to said sender registers, a dial in said digit controllingmechanism, means including said dial for controlling said revertivepulse fundamental circuit to establish circuits for said pulsing devices,when said dial is moved forward away from its t normal position, andafter it `has been moved Y forward and released, for regulating thenumber of pulses in a digittransmitted byy said sender pulsing devicesfor setting the registers of said senders for controlling the switchingconnection between said incoming line anda particular outgoing line. Y

10. In a telephone switching system, register mechanism, a revertivepulse fundamental circuit of the type having pulse transmitting devicescontrolled by the shunt method and having a relay which'is operable when`the fundamental circuit is closed, said relay establishing a connectingcircuit between said register mechanism and said pulsing devices forsetting said registers responsive to the operations of said pulsingdevices, a digit pulse controlling mechanism forY saidfundamentalcircuit having a telephone dial,

means in said dial for causing the closure of sa-id fundamental circuitwhen moved away from its normal position, a shunt device, and othermeans in said dial intermittently operated as said dial restores to itsnormal position for controlling said shunt device for regulating thenumber of operations of said pulsing devices for a digit for settingsaid registering mechanism.

il. In a telephone switching system, a sender having registers forcontrolling switching operations, a revertive pulse fundamental circuitof the type having a` stepping relay and a pulsing relay controlled bythe shunt method and having a line relay which is operable when thefundamental circuit is closed, said line relay establishing a connectingcircuit between said sender registers and said pulsing relay for settingthe registers responsive to the operations of said stepping and pulsingrelays, a digit pulse control mechanism for said fundamental circuithaving a telephone dial,` means in said dial for causing the closure ofsaid fundamental circuit when moved away from its normal position, ashunt device and other means in said dial intermittently operated assaid dial restores to its normal position for controlling said shuntdevice for regulating the number of operations of said stepping andpulsing relays for a digit for setting the registers of said'sender.

412. In a telephone switching system, a plurality of switch controllingsenders each having registers, a revertive pulse fundamental circuit foreach sender of the type having pulse transmitting devices controlled bythe shunt method and having a relay which is operable when thefundamental circuit is closed, the relay of each fundamental circuitestablishing a connecting circuit between the register mechanism and thepulsing devices in each sender for setting the registers responsive tothe operations of said pulsing devices, a single digit pulse controlmechanism for said plurality of fundamental circuits having a singletelephone dial, means in said dial for causing the closure of saidfundamental circuits when moved away from its normal position, a shuntdevice in said control mechanism and other means in said dialintermittently operated as said dial restores to its normal position.for controlling said shunt device for regulating the number ofoperations of said pulsing devices for a digit for setting theregistering mechanism of all of said plurality of senders.

13. In a telephone switching system, a switch controlling circuit havingregisters, a digit controlling circuit, Va revertive pulse fundamentalcircuit extending from said switch controlling circuit to said digitcontrolling circuit, the switch controlling `circuit portion'of saidfundamental circuit comprising a relay operable by said digitcontrolling circuit during non-pulsing periods for arranging said switchcontrolling circuit for receiving pulses, a pulsing device for operatingsaid switch controlling circuits and for holding said relay operated.during the pulse transmitting period, the digit controlling portion ofsaid fundamental circuit comprsing a telephone dial, contact springs insaid dial which arey open when the dial is in its normal position andclosed when the dial is moved away from its normal position, othercontact springs in said dial which are intermittently opened andclosedduring the restoring movement of said dial, means under the control ofsaid rst springs for `closing said fundamental circuit when said dial ismoved away from its normal position, and a shunt device under thecontrol of said other springs for controlling the number of operationsof said pulsing devices for a digit for setting the registers of saidswitch controlling circuit.

14. In an automatic telephone system, a sender register controlmechanism 'comiected to a revertive pulse fundamental circuit of thetype in which relays including a stepping relay are operated when thefundamental circuit is closed for transmitting pulses to a register andthe stepping relay is released yloy the application of a shunt to a legof the fundamental circuit as each pulse is transmitted, a digit pulsecontrolling telephone dial, contacts in said dial connected with saidfundamental circuit for closing the fundamental circuitwhen said dial ismoved away from its normal position and other contacts in said dialintermittently opened andclosed on its return movement to its normalposition for regulating the number of times said step-ping relay isoperated and released for the pulses of a digit and a relay under thecontrol'of said shunt and said Yshunt to a leg of the fundamentalcircuit as each pulse is transmitted, a digit pulse controllingtelephone dial, contacts in said dial connected With said fundamentalcircuit' for closing the fundamental circuit when said dial is movedaway from its normal position and other contaots in said dialintermittently opened and f closed on its return movement to its normalposition for regulating the number of times said 20 stepping relay isoperated and released for ythe pulses of a digit,oa synchronizing relayin said fundamental circuit released by said shunt simultaneously withthe release of said stepping relay and a contact on said synchronizingrelay in a 25 circuit controlled by said other dial contacts forsynchronizing the operations of said stepping relay with the operationsof said other dial contacts.

BARTH VANDER. ELS.

